โดเมน ช่วยเหลือ

What is DNS?

Video transcript

Hi there. In this video, you’ll learn about a crucial part of the Internet - the Domain Name System or DNS.

So what is DNS? Well, it’s a translation system that allows us humans to search the Internet using language we’re comfortable with. Without DNS, the Internet as we know it would not exist.

For example, you couldn’t do your shopping online; you’d have to drive to an actual store to buy your things. There would be no way to stream music or videos to your smartphone, and no way to video chat with a friend across the ocean, or even across the street. But what does DNS have to do with this?

The Internet is made up of computers that are set up in large networks around the world. These networks are connected by a web of underground and, in some cases, undersea wires.

Computers on the Internet communicate with each other using strings of numbers called Internet Protocol or IP addresses.

IP addresses function like street addresses - they identify where a computer is located on the Internet and help guide the information traveling between computers.

Now it’s one thing for computers to communicate using strings of numbers, but imagine if we humans had to memorize these seemingly random strings of numbers for every single website we wanted to find - not very realistic, huh? Well because of DNS, we don’t have to.

DNS translates the human-friendly domain names that we’re comfortable using, into the IP addresses that computers need to communicate with one another. The process starts with you and your web browser.

When you type a domain name into your web browser, your browser and computer determine if one of them already has the domain’s related IP address in their memory.

If it’s a domain you’ve visited recently - like the newspaper website you visit every morning, your browser may have stored the domain name and its IP address in memory, and can display the website in a split second.

If the domain isn’t hanging around in local memory, your computer takes the search out to the Internet, where it asks, or queries, a series of DNS servers, if they have the domain name in their memory or database.

The first DNS server that receives the query, checks its memory for the domain name. If it doesn’t find the domain name in its memory, it sends the query on to the next DNS server to see if it can help.

As soon as the domain name is found on a DNS server, that server returns the domain name and its associated IP address to the requesting DNS server, and on down the line until it arrives back at your computer.

Each time a requesting DNS server receives a domain name and IP address, the server stores the information in its memory, so any future requests for the domain name can be answered more quickly.

Once your computer has the IP address for the domain name, your browser knows where to find it on the Internet.

Your browser uses your computer to communicate with the server where the domain name is hosted and requests any associated files.The host server returns the files which then display your web browser.

Our ability to use domain names to quickly and easily retrieve websites and files from the Internet is entirely dependent on this tightly integrated and tiered line of communication.

So the next time you buy a pair of shoes online, listen to some music on your smartphone or video chat with a friend on another continent… remember, it’s not magic that lets you do things on the web - it’s DNS.